Correlation system



Se t. 29, 1959 M. MAsoNsoN coRRELAToN sYSTEM Fi1ed APri1 2 1957 the diffefence signal to the contfoI gTids 30 and 31 TesultS in an output signal at 36 Which is pfopoftional to the Squae of the input signal (I Z The outpUt Signal at 35 Which iS the squafed diffeTence- SignaI iS paSSed to the^ integrating cifcuit 37 Whefeat thefe iS pef fofIned an integfating opefation. TheTe is shunted acroSS fhe integrating circuit 37 an indicating device 38 Which indicates the .value of the integfated signal vvhich in effect is an indication of the coffelation between the two in ut si nals v (r) and M (z). A Sefies of in ut si nals (f) ffoIn the libfary Source iS conlpared With M (z) and When a pafticulaf Signal Z (Z) gives lise to a n1iniInum indication, then thefe iS a best nlatch ac cofding to the leaSt n1eanS squafed diffefence.

The scfeen gfidS of the pentodes 32 and 33 afe Shown to be coupled to two different potentiaIs v and WheTe .by the contfol gfid cutoff pointS of the pentodes 32 and 33 afe so adiuSted that the combined chaTacteIiSticS of the pentodes in paTaHel can effect an incfeaSe in the Tange of squafe law detection aS compafed to a single pentode.

In Fig. Z the coffelation device iS Shovvn aS paTt of a phaSe detecting affangement. The cofrelation device 4Z opefates in the Same faShion aS vvaS descfibed above iI1 connection with Fig. 1. z LSSume that the obiect of the arfangeInent in Fig. Z is to coInpafe two signalS Which aTe identical eXcepting fof the haSe felationShip. II1 oTdeT to pTovide fof a mofe Stable opefation, the amplifief 45 is choSen to have a pTedeterInined thfeshold leve1 above which the out ut Signal of the corfelation device nlust be nlaintained in ofdef to opefate the SeTvo loop. Tho nean squafed difference Signal is aIIlplified at 45 to drive the sefvo motof 45 Which in tufn adiustS the phase shiftef 43 until the haSe of the Signal ffon1 Soufce 40 and the Signal ffom SoUfce 41 iS idenficaL vVhen the two signalS afe in phaSe, the ontput of the coffelation device win be at a T1iniInUn1 of nUn and the SeTvo Inotof 45 win no longef be dfiven to adiLlSt the phase shifte1 43. There iS attached to the phase Shiftef 43, an in dicating device 44 Which indicateS tho diffeTence betWeen the phase of the Signal being feceived ffon1 soufce 40 and the Signal being Teceived ffon1 soUfce 41.

X Vhile I have described above the TincipleS of IIly in vention in connection vvith Specific appofatuS, it iS to be clearly undeTStood that this descripton is Inade only by way of exaInpe and not as a lin1itation to the Scope of nly invention as set fofth in the obiectS thereof and in the occofnpanying clain1s.

I claim= L A corfelation device fof deterfnining the cofrelation between a fifst and Second input signal con1pfising a fSt and Second input Signal source, Subtraction fneanS coupled to said input soufces fof subtfacting said fifSt signal ffom said second Signal to obtain a diffefence signal, Ineans coupled to said subtTacfion Ineans fo1 Squafing said diffefence signal, and inte fatin means cou led to said SquaTing IneanS to integrate said output to obtain a coffelation signal TepreSentative of the coffelation be tween Said fi1St and Said second input Signals.

2. A cofrelation device for deterIT1infng the cofrelation betWeen a fifSt and Second input Signal conlpfising a fifSt and second inpL1t Signal Source, SubtTaction n1eans conpled to said inp11t sources f()f SUbtTacting Said firSt Signa1 ffoIn Said second Signal to obtain a diffefence SignaL fneans coupled to said sI1btfaction IneanS foT SquaTing Said diffef ence signaL integfating nleans coUpled to Said Squafing IneanS to integTate said output and indicating neanS coUpled fo said integfating fneanS to indicate the value of the integfated signal thefeat. v

3. A correlation device fof deteTInining the coffelation betWeen a firSt and Second input signal con1prising a fst and seCondfnputsignal Soufce, SUbtfaction nleanS coupled said second si nal to obtain a difference signaL deriving meanS coUpIed to said Subtfaction meanS fof deTiving froIn said diffetence si nal a direct cntrent volta e ro ortional to the aInplitude thefeof, Ineans coupled to Said defiving TneanS fof pfoducing an oUtput signal propoftional to the squaTe of Said voltage signaL integfating IneanS coupled to Said Squafing TneanS to integfate said ontput and indicating nleans conpled to Said integfating means to indicate the value of the integrated Signal thefeat.

4. A coffelation device according to clain1 3 vhefein Said SUbffaction nTeanS inclIldeS a tranSfoffnef having a pfimafy and secondafy Sides, Said pTinlafy Side having itS opposite ends feSpectively coupled to an associated one of said input teTn1inals and having itS nlidpoint tapped to a first fefefence potential, and said secondafy side havfg itS fnidpofnt tapped to a Second feference potontiaL 5. A corfelation device accofding to cain1 3, vvhefein Said defivfng fneanS includeS a fifst and second diodo, one each of which is coupled to an aSSociated opposito end of the secondaTy Side of Said tTansfofmef to effect a fuH vave fecti0catfon of Said difference SignaL 6. A coffelation device accofding to claim 3, Whefein said Ineans fo1 squafing said difference Signal includeS a Squafe law detectof neans.

7, A coffelation device according to claim 3, Whefen said means for squafing Said difference signal coInpfises a fifSt and Second pentode conpled in paTaHe havfng square 1av characteriSticS Said fifSt pentode having the vohage supply of its scfeen gfid at a fifSt potentia and said Second pentode having the voltage supply of its Scfeen gfid at a Second potential diffefing from Said nfst potential such that the chaTacteriStic Tegion for square la W detection is increased by the conbination ovef that of a single pentode.

8, A coffelation device for detefInining the coffelatfon betvveen a fifst and Second input Signal cofnpfiSing a fifSt and Second in nt si nal soufce, a first and second amplifief feSpectively coupled to an associafed input soUrce, a tranSfofInef having a pTiInafy and a secondary Winding to subffact Said nfSt Signal ffom said second signal and obtain a diffefence SignaL Said pfiInaTy Side having its opposite ends feSpectively coupled to an aSSociated one of the outputS of Said aTflpliHers and having its IT1idpoint tapped to a first fefefence potentia1, said Secondary Side having its n1id oint tap ed to a Second Tefefence oten tial to effect a negative value of said difference Signal between one of itS ends and Said midpoint and to effect a positive value of Said diffefence Signal between the othef end and Said midpoint, a fffSt and second diode fe- Spectively coupled to an associated end of said secondary side to eect a fuH vvave rectification of Said difference SignaL cifcI1itTy Ineans coupHng the out utS of said diodeS, a fifst and second pentode each having Square laW chalactefiStics and each having their fospecfive contfol gfids coUpled to said ci1cUitry menns to effect a square Iaw an1pli0cation of Said dfffefence SignaI, Said fiTSt pentodo having itS Scfeen gfid coupled to a fifSt biaS potentiaL Said Second pentode having itS Scfeen gfid coUpled to a Second biaS potential to incTeaSe the charactefisfic square law fegion When Said fi1st and said Second pentodo aTe coupled in pafaHeL an integTating cifcuit coupled to thc output of said pentodes fo integfate the signal thefeffom and indicatng Ineans coupled to said integrating cifcuit to indicate the value of the integrated Signal thefeat.

9. A phase detecting aTTangement fo1 determining the phaSe felationShip befween two signalS corlpfiSing a nTSf and Second input Signal Soufce, a vafiable phaSe shffting nleanS including an indicating IneanS, Subtfaction Ineans cifcuitry conpled fespectively fo Said fifSt input sourCo and thfo11gh Said phase Shifting meanS to said second input source fo1 subtfacting said fifSt Signal ffofn Said Second Signal to obtain a diffefence Signal, TneanS coupled to said Subtraction IneanS for squaring said difference signal, integfating Ineans conpled to Said Squaring Tneans 

